The present invention relates to a cap for fuel tanks of vehicles and, more particularly, to a cap for fuel tanks constructed to avoid the leak of fuel out of the tank in the event of a collision of the vehicle.
A known cap for fuel tank having a function to prevent the leak of fuel in the event of a collision involves a groove or fragile portion formed in the portion thereof intermediate between the cap body and the lid member. When an extraordinary external force is exerted on the lid member, the fragile portion is broken to permit the cap member to be separated from the cap body, so that the cap body remains in the filler neck of the tank to prevent any leak of the fuel out of the tank. This type of cap is shown, for example, in Japanese Patent Laid-Open No. 55950/1980, Japanese Utility Model Publication No. 18288/1982 and U.S. Pat. No. 4,177,931. In this conventional cap, however, there is no means to assure the breakage of the cap at the fragile portion for leaving only the cap body in the filler neck, and it has been often experienced that the cap body itself is broken to permit the leak of fuel.
The present invention aims as its primary object at providing a cap for fuel tanks, improved to ensure an easy separation of the lid member to leave the cap body intact in the filler neck of the tank without fail, thereby to prevent leak of fuel from the fuel tank.
To this end, according to the invention, there is provided a cap for a fuel tank comprising: a cap body screwed into the filler neck of the fuel tank with an "O" ring interposed therebetween, the cap body having an upper flange provided with a plurality of engaging grooves or engaging holes or engaging tabs; and a lid member provided in the lower side thereof with a plurality of engaging tabs or engaging grooves or engaging holes; whereby said lid member is attached to said cap body through the mutual engagement between the engaging projections and the engaging recesses.
Alternatively, the cap body may have its upper flange provided with a plurality of engaging recesses or engaging projections formed in the inner surface or outer surface of the wall thereof; the lid member having a slitted sleeve projecting from the lower side thereof and provided with a plurality of engaging projections or engaging recesses formed in the outer surface or the inner surface of the sleeve; whereby the lid member is attached to the cap body through the mutual engagement between the engaging projections and the engaging recesses. The recesses are preferrably shaped to permit the lid member to slip relative to the cap member in one direction, as on tightening, but not in the other direction, as on loosening.
In any event, the lid member normally remains mated to the cap body but is separable from the cap body to leave the cap body intact within the filler neck upon application of external force to the lid member, such as, through collision.